1. Field of the Invention
The present invention relates to image-information converting apparatuses and methods, image displaying apparatuses and methods, coefficient calculating apparatuses and methods, coefficient-data storing apparatuses and methods, apparatuses and methods for detecting a part where picture quality is degraded, recording media, and programs. More specifically, the present invention relates to an image-information converting apparatus and method, an image displaying apparatus and method, a coefficient calculating apparatus and method, a coefficient-data storing apparatus and method, and an apparatus and method for detecting a part where picture quality is degraded, a recording medium, and a program.
2. Description of the Related Art
Techniques of converting a composite video signal into a component video signal are becoming widespread. As an example of video signals, NTSC (National Television Standards Committee) video signals are widely used.
FIG. 1 is an example configuration of a television receiver that is relevant to the present invention. Referring to FIG. 1, a tuner 2 demodulates a signal received by an antenna 1, and outputs a demodulated signal to a video intermediate-frequency processing circuit (VIF circuit) 3. A composite video signal processed in and output from the VIF circuit 3 is input to a Y/C (Y: luminance signal, C: chroma signal) separation circuit 4. The Y/C separation circuit 4 separates the composite video signal input thereto into a luminance signal Y and a chroma signal C, outputting these signals to a matrix circuit 6 and a chroma demodulation circuit 5, respectively. The chroma demodulation circuit demodulates the chroma signal C input thereto, generating color-difference signals R-Y and B-Y, which are fed to the matrix circuit 6. The matrix circuit 6 generates RGB primary-color signals from the luminance signal Y, and the color-difference signals R-Y and B-Y input thereto, and outputs the RGB signals to a display device 7 for display.
Now, the operation of the television receiver will be described. The tuner 2 receives, via the antenna 1, an electromagnetic wave of a broadcasting station of a channel specified by a user, and outputs a demodulated signal to the VIF circuit 3. The VIF circuit 3 processes the signal output from the tuner 2, and outputs, for example, an NTSC composite video signal to the Y/C separation circuit 4. The Y/C separation circuit 4 separates the composite video signal into a luminance signal Y and a chroma signal C, outputting the luminance signal Y and the chroma signal C to the matrix circuit 6 and the chroma demodulation circuit 5, respectively.
The chroma demodulation circuit 5 demodulates the chroma signal C input from the Y/C separation circuit 4, thereby generating color-difference signals R-Y and B-Y. The matrix circuit 6 combines the luminance signal Y fed from the Y/C separating circuit 4 and the color-difference signals R-Y and B-Y fed from the chroma demodulation circuit 5 to generate RGB primary-color signals, which are output to the display device 7 for display.
FIG. 2 shows another example configuration of a television receiver that is relevant to the present invention. Although the basic configuration is the same as that of the television receiver shown n FIG. 1, in FIG. 2, a resolution converter circuit 11 is provided. The resolution converter circuit 11 changes the resolution based on the luminance signal Y fed from the Y/C separation circuit 4 and the color-difference signals R-Y and B-Y fed from the chroma demodulation circuit 5, and executes so-called IP conversion (Interlace/Progressive conversion), and so forth, outputting the results to the matrix circuit 6. The operation of the television receiver shown in FIG. 2 additionally includes conversion of resolution and IP conversion executed by the resolution converter circuit 11 as compared with the operation of the television receiver shown in FIG. 1.
As described above, in the television receivers relevant to the present invention, a composite video signal is first separated into a luminance signal Y and a chroma signal C in the Y/C separation circuit 4, and the chroma signal C is then demodulated to form a component signal including a baseband luminance signal Y and color-difference signals R-Y and B-Y. The component signal is then converted into RGB primary-color signals by the matrix circuit 6. Thus, the circuitry is complex and large in size, resulting in high cost.
Although filters including two-dimensional Y/C separation circuit and three-dimensional Y/C separation circuits have been proposed in order to solve the problems described above, the filters are susceptible to degradation in picture quality due to error in Y/C separation, such as dot interference or cross color.